Paginate leaderboard; cache rows instead of rendered page

core/templates/core/leaderboard.html

@@ -54,11 +54,12 @@ <h2 class="font-heading font-semibold text-xl text-on-surface">Classement</h2>
         {% if profiles %}
         <div class="space-y-2.5">
             {% for p in profiles %}
+            {% with rank=forloop.counter0|add:page_obj.start_index %}
             <a href="{% url 'profile' p.github_username %}" class="group flex items-center gap-4 bg-surface-container-lowest border border-outline-variant/40 rounded-xl p-3.5 pl-4 shadow-card hover:shadow-card-hover hover:border-primary/20 transition-all relative overflow-hidden focus-visible:outline focus-visible:outline-2 focus-visible:outline-primary">
-                {% if forloop.counter <= 3 %}
-                <span class="absolute left-0 top-0 bottom-0 w-1 {% if forloop.counter == 1 %}bg-primary{% elif forloop.counter == 2 %}bg-secondary-container{% else %}bg-tertiary{% endif %}"></span>
+                {% if rank <= 3 %}
+                <span class="absolute left-0 top-0 bottom-0 w-1 {% if rank == 1 %}bg-primary{% elif rank == 2 %}bg-secondary-container{% else %}bg-tertiary{% endif %}"></span>
                 {% endif %}
-                <span class="w-8 text-center font-display font-semibold text-lg shrink-0 {% if forloop.counter <= 3 %}text-primary{% else %}text-on-surface-variant{% endif %}">{{ forloop.counter }}</span>
+                <span class="w-8 text-center font-display font-semibold text-lg shrink-0 {% if rank <= 3 %}text-primary{% else %}text-on-surface-variant{% endif %}">{{ rank }}</span>
                 {% if p.avatar_url %}
                 <img src="{{ p.avatar_url }}" alt="" class="w-11 h-11 rounded-xl object-cover bg-surface-container shrink-0" loading="lazy">
                 {% else %}
@@ -73,8 +74,44 @@ <h2 class="font-heading font-semibold text-xl text-on-surface">Classement</h2>
                     <div class="text-xs text-on-surface-variant">contrib.</div>
                 </div>
             </a>
+            {% endwith %}
             {% endfor %}
         </div>
+
+        {% if page_obj.paginator.num_pages > 1 %}
+        {% with qs=querystring %}
+        <nav class="flex items-center justify-center gap-1.5 mt-10" aria-label="Pagination">
+            {% if page_obj.has_previous %}
+            <a href="?{{ qs }}{% if qs %}&{% endif %}page={{ page_obj.previous_page_number }}"
+               class="w-10 h-10 grid place-items-center rounded-lg border border-outline-variant/60 text-on-surface-variant hover:bg-surface-container transition-colors">
+                <span class="material-symbols-outlined text-[20px]">chevron_left</span>
+            </a>
+            {% endif %}
+
+            {% for num in page_obj.paginator.page_range %}
+                {% if num == page_obj.number %}
+                <span class="min-w-10 h-10 px-3 grid place-items-center rounded-lg bg-primary text-on-primary font-semibold">{{ num }}</span>
+                {% elif num >= page_obj.number|add:-2 and num <= page_obj.number|add:2 %}
+                <a href="?{{ qs }}{% if qs %}&{% endif %}page={{ num }}"
+                   class="min-w-10 h-10 px-3 grid place-items-center rounded-lg border border-outline-variant/60 text-on-surface-variant hover:bg-surface-container transition-colors">{{ num }}</a>
+                {% elif num == 1 or num == page_obj.paginator.num_pages %}
+                <a href="?{{ qs }}{% if qs %}&{% endif %}page={{ num }}"
+                   class="min-w-10 h-10 px-3 grid place-items-center rounded-lg border border-outline-variant/60 text-on-surface-variant hover:bg-surface-container transition-colors">{{ num }}</a>
+                {% elif num == page_obj.number|add:-3 or num == page_obj.number|add:3 %}
+                <span class="w-6 text-center text-on-surface-variant">…</span>
+                {% endif %}
+            {% endfor %}
+
+            {% if page_obj.has_next %}
+            <a href="?{{ qs }}{% if qs %}&{% endif %}page={{ page_obj.next_page_number }}"
+               class="w-10 h-10 grid place-items-center rounded-lg border border-outline-variant/60 text-on-surface-variant hover:bg-surface-container transition-colors">
+                <span class="material-symbols-outlined text-[20px]">chevron_right</span>
+            </a>
+            {% endif %}
+        </nav>
+        {% endwith %}
+        {% endif %}
+
         {% else %}
         <div class="text-center py-16 px-4 bg-surface-container-low/50 rounded-2xl">
             <span class="material-symbols-outlined text-[40px] text-on-surface-variant">groups</span>
@@ -85,4 +122,4 @@ <h3 class="font-heading font-semibold text-lg text-on-surface mt-3">Personne ici
         {% endif %}
     </div>
 </div>
-{% endblock %}
+{% endblock %}

core/tests.py

@@ -273,3 +273,63 @@ def test_explore_clone_size_filter_pagination(client, max_size, htmx):
     assert response.context["page_obj"].number == 2
     assert len(response.context["page_obj"]) == 1
     assert b"Excluded boundary" not in response.content
+
+
+@pytest.mark.django_db
+def test_leaderboard_pagination(client, monkeypatch):
+    cache.clear()
+    # Small page size so we don't need 50+ users. The view reads this module
+    # constant at request time, so patching it works.
+    monkeypatch.setattr("core.views.LEADERBOARD_PAGE_SIZE", 2)
+
+    # lbuser{i} has i contributions. Odd i -> Ghana (1, 3, 5), even -> Nigeria (2, 4).
+    for i in range(1, 6):
+        user = User.objects.create_user(f"lbuser{i}")
+        profile = user.profile  # created by signal
+        profile.github_username = f"lbuser{i}"
+        profile.country = "Ghana" if i % 2 else "Nigeria"
+        profile.save()
+        Contribution.objects.bulk_create([
+            Contribution(
+                user=user, repo_full_name="a/b", title=f"pr{j}",
+                pr_url=f"https://example.com/{i}/{j}",
+            )
+            for j in range(i)
+        ])
+
+    url = reverse("leaderboard")
+
+    # Page 1: hero shown, highest contributor first, 2 rows.
+    r1 = client.get(url)
+    assert r1.status_code == 200
+    assert r1.context["page_obj"].number == 1
+    assert [p.github_username for p in r1.context["profiles"]] == ["lbuser5", "lbuser4"]
+    assert r1.context["top"].github_username == "lbuser5"
+
+    # Page 2: no hero, ranks continue from 3.
+    r2 = client.get(url, {"page": 2})
+    assert r2.status_code == 200
+    assert r2.context["top"] is None
+    assert r2.context["page_obj"].start_index() == 3
+    assert [p.github_username for p in r2.context["profiles"]] == ["lbuser3", "lbuser2"]
+
+    # Bad or out-of-range page numbers must not crash.
+    assert client.get(url, {"page": "abc"}).status_code == 200
+    assert client.get(url, {"page": 999}).status_code == 200
+
+    # Country filter: 3 Ghana profiles -> 2 pages, and every page link keeps ?country=Ghana.
+    r3 = client.get(url, {"country": "Ghana"})
+    assert r3.status_code == 200
+    assert r3.context["page_obj"].paginator.num_pages == 2
+    links = re.findall(r'href="([^"]+)"', r3.content.decode())
+    page_links = [link for link in links if "page=" in link]
+    assert page_links
+    for link in page_links:
+        query = parse_qs(urlsplit(unescape(link)).query)
+        assert query["country"] == ["Ghana"]
+
+    next_page = next(link for link in page_links if "page=2" in link)
+    r4 = client.get(url + "?" + urlsplit(unescape(next_page)).query)
+    assert r4.status_code == 200
+    assert r4.context["page_obj"].number == 2
+    assert [p.github_username for p in r4.context["profiles"]] == ["lbuser1"]

core/views.py

@@ -21,6 +21,9 @@
 # Number of issues per page in the explore view.
 PAGE_SIZE = 30
 
+# Number of contributors per page on the leaderboard.
+LEADERBOARD_PAGE_SIZE = 50
+
 # Fields needed by issue cards / explore list (avoid pulling full body blobs).
 ISSUE_LIST_FIELDS = (
     "id",
@@ -207,19 +210,23 @@ def profile_view(request, username):
 
 def leaderboard(request):
     country = request.GET.get("country", "").strip()
-    lb_key = cache_key("leaderboard", country or "all")
-    cached = cache_get(lb_key)
-    if cached is not None:
-        return HttpResponse(cached)
 
-    profiles = (
-        Profile.objects.select_related("user")
-        .annotate(total=Count("user__contributions"))
-        .filter(total__gt=0)
-        .order_by("-total")
-    )
-    if country:
-        profiles = profiles.filter(country__iexact=country)
+    # Cache only the computed rows (not rendered HTML), so the template is
+    # rendered per request. This also fixes #38 (anonymous navbar served to
+    # logged-in users) and means pagination doesn't need page in the key.
+    rows_key = cache_key("leaderboard", "rows", country.lower() or "all")
+    profiles = cache_get(rows_key)
+    if profiles is None:
+        qs = (
+            Profile.objects.select_related("user")
+            .annotate(total=Count("user__contributions"))
+            .filter(total__gt=0)
+            .order_by("-total", "pk")  # pk tiebreaker = stable ranking across pages
+        )
+        if country:
+            qs = qs.filter(country__iexact=country)
+        profiles = list(qs)  # no [:50] slice any more
+        cache_set(rows_key, profiles, CACHE_TTL)
 
     countries_key = cache_key("leaderboard", "countries")
     countries = cache_get(countries_key)
@@ -233,23 +240,37 @@ def leaderboard(request):
         )
         cache_set(countries_key, countries, CACHE_TTL)
 
-    profiles = list(profiles[:50])
-    top = profiles[0] if profiles else None
+    paginator = Paginator(profiles, LEADERBOARD_PAGE_SIZE)
+    # get_page() handles ?page=abc and out-of-range values safely.
+    page_obj = paginator.get_page(request.GET.get("page", "1"))
+    page_rows = list(page_obj.object_list)
 
-    response = render(
+    on_first_page = page_obj.number == 1
+    if on_first_page:
+        podium, rest = page_rows[:3], page_rows[3:]
+    else:
+        podium, rest = [], page_rows
+
+    # Rank of the row just before `rest` begins: 3 on page 1, 50 on page 2, ...
+    rest_offset = max(page_obj.start_index() - 1, 0) + (len(podium))
+
+    querystring = urlencode({"country": country}) if country else ""
+
+    return render(
         request,
         "core/leaderboard.html",
         {
-            "profiles": profiles,
-            "podium": profiles[:3],
-            "rest": profiles[3:],
-            "top": top,
+            "profiles": page_rows,
+            "podium": podium,
+            "rest": rest,
+            "rest_offset": rest_offset,
+            "top": profiles[0] if (profiles and on_first_page) else None,
+            "page_obj": page_obj,
+            "querystring": querystring,
             "countries": countries,
             "selected_country": country,
         },
     )
-    cache_set(lb_key, response.content, CACHE_TTL)
-    return response
 
 
 @require_http_methods(["GET", "HEAD"])